Leguminous vegetable (3)
I believe the answer is:
pea
'leguminous vegetable' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for pea that I've seen before include "Vegetable in a whistle" , "The plant is a strange ape" , "veg" , "Ape this plant awkwardly" , "Common vegetable seed from pod" .)